Sleep Modes

[中文]

Overview

ESP32 supports two major power saving modes: Light-sleep and Deep-sleep. According to the features used by an application, there are some sub sleep modes. See Sleep Modes for these sleep modes and sub sleep modes. Additionally, there are some power-down options that can be configured to further reduce the power consumption. See Power-down Options for more details.

There are several wakeup sources in the sleep modes. These sources can also be combined so that the chip will wake up when any of the sources are triggered. Wakeup Sources describes these wakeup sources and configuration APIs in detail.

The configuration of power-down options and wakeup sources are optional. They can be configured at any moment before entering the sleep modes.

Then the application can call sleep start APIs to enter one of the sleep modes. See Entering Sleep for more details. When the wakeup condition is met, the application is awoken from sleep. See Checking Sleep Wakeup Cause on how to get the wakeup cause, and Disable Sleep Wakeup Source on how to handle the wakeup sources after wakeup.

Sleep Modes

In Light-sleep mode, the digital peripherals, most of the RAM, and CPUs are clock-gated and their supply voltage is reduced. Upon exit from Light-sleep, the digital peripherals, RAM, and CPUs resume operation and their internal states are preserved.

In Deep-sleep mode, the CPUs, most of the RAM, and all digital peripherals that are clocked from APB_CLK are powered off. The only parts of the chip that remain powered on are:

• RTC controller

• ULP coprocessor

• RTC FAST memory

• RTC SLOW memory

Wi-Fi/Bluetooth and Sleep Modes

In Deep-sleep and Light-sleep modes, the wireless peripherals are powered down. Before entering Deep-sleep or Light-sleep modes, the application must disable Wi-Fi and Bluetooth using the appropriate calls (i.e., nimble_port_stop(), nimble_port_deinit(), esp_bluedroid_disable(), esp_bluedroid_deinit(), esp_bt_controller_disable(), esp_bt_controller_deinit(), esp_wifi_stop()). Wi-Fi and Bluetooth connections are not maintained in Deep-sleep or Light-sleep mode, even if these functions are not called.

If Wi-Fi/Bluetooth connections need to be maintained, enable Wi-Fi/Bluetooth Modem-sleep mode and automatic Light-sleep feature (see Power Management APIs). This allows the system to wake up from sleep automatically when required by the Wi-Fi/Bluetooth driver, thereby maintaining the connection.

Wakeup Sources

Wakeup sources can be enabled using esp_sleep_enable_X_wakeup APIs. Wakeup sources are not disabled after wakeup, you can disable them using esp_sleep_disable_wakeup_source() API if you do not need them any more. See Disable Sleep Wakeup Source.

Following are the wakeup sources supported on ESP32.

Timer

The RTC controller has a built-in timer which can be used to wake up the chip after a predefined amount of time. Time is specified at microsecond precision, but the actual resolution depends on the clock source selected for RTC_SLOW_CLK.

For details on RTC clock options, see ESP32 Technical Reference Manual > ULP Coprocessor [PDF].

RTC peripherals or RTC memories do not need to be powered on during sleep in this wakeup mode.

esp_sleep_enable_timer_wakeup() function can be used to enable sleep wakeup using a timer.

Touchpad

The RTC IO module contains the logic to trigger wakeup when a touch sensor interrupt occurs. To wakeup from a touch sensor interrupt, users need to configure the touch pad interrupt before the chip enters Deep-sleep or Light-sleep modes.

Revisions 0 and 1 of ESP32 only support this wakeup mode when RTC peripherals are not forced to be powered on (i.e., ESP_PD_DOMAIN_RTC_PERIPH should be set to ESP_PD_OPTION_AUTO).

esp_sleep_enable_touchpad_wakeup() function can be used to enable this wakeup source.

External Wakeup (ext0)

The RTC IO module contains the logic to trigger wakeup when one of RTC GPIOs is set to a predefined logic level. RTC IO is part of the RTC peripherals power domain, so RTC peripherals will be kept powered on during Deep-sleep if this wakeup source is requested.

The RTC IO module is enabled in this mode, so internal pullup or pulldown resistors can also be used. They need to be configured by the application using rtc_gpio_pullup_en() and rtc_gpio_pulldown_en() functions before calling esp_deep_sleep_start().

In revisions 0 and 1 of ESP32, this wakeup source is incompatible with ULP and touch wakeup sources.

esp_sleep_enable_ext0_wakeup() function can be used to enable this wakeup source.

Warning

After waking up from sleep, the IO pad used for wakeup will be configured as RTC IO. Therefore, before using this pad as digital GPIO, users need to reconfigure it using rtc_gpio_deinit() function.

External Wakeup (ext1)

The RTC controller contains the logic to trigger wakeup using multiple RTC GPIOs. One of the following two logic functions can be used to trigger ext1 wakeup:

• wake up if any of the selected pins is high (ESP_EXT1_WAKEUP_ANY_HIGH)

• wake up if all the selected pins are low (ESP_EXT1_WAKEUP_ALL_LOW)

This wakeup source is controlled by the RTC controller. Unlike ext0, this wakeup source supports wakeup even when the RTC peripheral is powered down. Although the power domain of the RTC peripheral, where RTC IOs are located, is powered down during sleep modes, ESP-IDF will automatically lock the state of the wakeup pin before the system enters sleep modes and unlock upon exiting sleep modes. Therefore, the internal pull-up or pull-down resistors can still be configured for the wakeup pin:

esp_sleep_pd_config(ESP_PD_DOMAIN_RTC_PERIPH, ESP_PD_OPTION_ON);
rtc_gpio_pullup_dis(gpio_num);
rtc_gpio_pulldown_en(gpio_num);

If we turn off the RTC_PERIPH domain, we will use the HOLD feature to maintain the pull-up and pull-down on the pins during sleep. HOLD feature will be acted on the pin internally before the system enters sleep modes, and this can further reduce power consumption:

rtc_gpio_pullup_dis(gpio_num);
rtc_gpio_pulldown_en(gpio_num);

If certain chips lack the RTC_PERIPH domain, we can only use the HOLD feature to maintain the pull-up and pull-down on the pins during sleep modes:

gpio_pullup_dis(gpio_num);
gpio_pulldown_en(gpio_num);

esp_sleep_enable_ext1_wakeup_io() function can be used to append ext1 wakeup IO and set corresponding wakeup level.

esp_sleep_disable_ext1_wakeup_io() function can be used to remove ext1 wakeup IO.

Note

Due to hardware limitation, when we use more than one IO for EXT1 wakeup, it is not allowed to configure different wakeup levels for the IOs, and there is corresponding inspection mechanism in esp_sleep_enable_ext1_wakeup_io().

Warning

• To use the EXT1 wakeup, the IO pad(s) are configured as RTC IO. Therefore, before using these pads as digital GPIOs, users need to reconfigure them by calling the rtc_gpio_deinit() function.

• If the RTC peripherals are configured to be powered down (which is by default), the wakeup IOs will be set to the holding state before entering sleep. Therefore, after the chip wakes up from Light-sleep, please call rtc_gpio_hold_dis to disable the hold function to perform any pin re-configuration. For Deep-sleep wakeup, this is already being handled at the application startup stage.

ULP Coprocessor Wakeup

ULP coprocessor can run while the chip is in sleep mode, and may be used to poll sensors, monitor ADC or touch sensor values, and wake up the chip when a specific event is detected. ULP coprocessor is part of the RTC peripherals power domain, and it runs the program stored in RTC SLOW memory. RTC SLOW memory will be powered on during sleep if this wakeup mode is requested. RTC peripherals will be automatically powered on before ULP coprocessor starts running the program; once the program stops running, RTC peripherals are automatically powered down again.

Revisions 0 and 1 of ESP32 only support this wakeup mode when RTC peripherals are not forced to be powered on (i.e., ESP_PD_DOMAIN_RTC_PERIPH should be set to ESP_PD_OPTION_AUTO).

esp_sleep_enable_ulp_wakeup() function can be used to enable this wakeup source.

GPIO Wakeup (Light-sleep Only)

In addition to EXT0 and EXT1 wakeup sources described above, one more method of wakeup from external inputs is available in Light-sleep mode. With this wakeup source, each pin can be individually configured to trigger wakeup on high or low level using gpio_wakeup_enable() function. Unlike EXT0 and EXT1 wakeup sources, which can only be used with RTC IOs, this wakeup source can be used with any IO (RTC or digital).

esp_sleep_enable_gpio_wakeup() function can be used to enable this wakeup source.

Warning

Before entering Light-sleep mode, check if any GPIO pin to be driven is part of the VDD_SDIO power domain. If so, this power domain must be configured to remain ON during sleep.

For example, on ESP32-WROOM-32 board, GPIO16 and GPIO17 are linked to VDD_SDIO power domain. If they are configured to remain high during Light-sleep, the power domain should be configured to remain powered ON. This can be done with esp_sleep_pd_config():

esp_sleep_pd_config(ESP_PD_DOMAIN_VDDSDIO, ESP_PD_OPTION_ON);

UART Wakeup (Light-sleep Only)

When ESP32 receives UART input from external devices, it is often necessary to wake up the chip when input data is available. The UART peripheral contains a feature which allows waking up the chip from Light-sleep when a certain number of positive edges on RX pin are seen. This number of positive edges can be set using uart_set_wakeup_threshold() function. Note that the character which triggers wakeup (and any characters before it) will not be received by the UART after wakeup. This means that the external device typically needs to send an extra character to the ESP32 to trigger wakeup before sending the data.

esp_sleep_enable_uart_wakeup() function can be used to enable this wakeup source.

After waking-up from UART, you should send some extra data through the UART port in Active mode, so that the internal wakeup indication signal can be cleared. Otherwises, the next UART wake-up would trigger with two less rising edges than the configured threshold value.

Disable Sleep Wakeup Source

Previously configured wakeup sources can be disabled later using esp_sleep_disable_wakeup_source() API. This function deactivates trigger for the given wakeup source. Additionally, it can disable all triggers if the argument is ESP_SLEEP_WAKEUP_ALL.

Power-down Options

The application can force specific powerdown modes for RTC peripherals and RTC memories. In Deep-sleep mode, we can also isolate some IOs to further reduce current consumption.

Power-down of RTC Peripherals and Memories

By default, esp_deep_sleep_start() and esp_light_sleep_start() functions power down all RTC power domains which are not needed by the enabled wakeup sources. To override this behaviour, esp_sleep_pd_config() function is provided.

Note: in revision 0 of ESP32, RTC FAST memory is always kept enabled in Deep-sleep, so that the Deep-sleep stub can run after reset. This can be overridden, if the application does not need clean reset behaviour after Deep-sleep.

If some variables in the program are placed into RTC SLOW memory (for example, using RTC_DATA_ATTR attribute), RTC SLOW memory will be kept powered on by default. This can be overridden using esp_sleep_pd_config() function, if desired.

Power-down of Flash

By default, to avoid potential issues, esp_light_sleep_start() function does not power down flash. To be more specific, it takes time to power down the flash and during this period the system may be woken up, which then actually powers up the flash before this flash could be powered down completely. As a result, there is a chance that the flash may not work properly.

So, in theory, it is ok if you only wake up the system after the flash is completely powered down. However, in reality, the flash power-down period can be hard to predict (for example, this period can be much longer when you add filter capacitors to the flash's power supply circuit) and uncontrollable (for example, the asynchronous wake-up signals make the actual sleep time uncontrollable).

Warning

If a filter capacitor is added to your flash power supply circuit, please do everything possible to avoid powering down flash.

Therefore, it is recommended not to power down flash when using ESP-IDF. For power-sensitive applications, it is recommended to use Kconfig option CONFIG_ESP_SLEEP_FLASH_LEAKAGE_WORKAROUND to reduce the power consumption of the flash during Light-sleep, instead of powering down the flash.

It is worth mentioning that PSRAM has a similar Kconfig option CONFIG_ESP_SLEEP_PSRAM_LEAKAGE_WORKAROUND.

However, for those who have fully understood the risk and are still willing to power down the flash to further reduce the power consumption, please check the following mechanisms:

• Setting Kconfig option CONFIG_ESP_SLEEP_POWER_DOWN_FLASH only powers down the flash when the RTC timer is the only wake-up source and the sleep time is longer than the flash power-down period.

• Calling esp_sleep_pd_config(ESP_PD_DOMAIN_VDDSDIO, ESP_PD_OPTION_OFF) powers down flash when the RTC timer is not enabled as a wakeup source or the sleep time is longer than the flash power-down period.

Note

• ESP-IDF does not provide any mechanism that can power down the flash in all conditions when Light-sleep.

• esp_deep_sleep_start() function forces power down flash regardless of user configuration.

Configuring IOs (Deep-sleep Only)

Some ESP32 IOs have internal pullups or pulldowns, which are enabled by default. If an external circuit drives this pin in Deep-sleep mode, current consumption may increase due to current flowing through these pullups and pulldowns.

To isolate a pin to prevent extra current draw, call rtc_gpio_isolate() function.

For example, on ESP32-WROVER module, GPIO12 is pulled up externally, and it also has an internal pulldown in the ESP32 chip. This means that in Deep-sleep, some current flows through these external and internal resistors, increasing Deep-sleep current above the minimal possible value.

Add the following code before esp_deep_sleep_start() to remove such extra current:

rtc_gpio_isolate(GPIO_NUM_12);

Entering Sleep

esp_light_sleep_start() or esp_deep_sleep_start() functions can be used to enter Light-sleep or Deep-sleep modes correspondingly. After that, the system configures the parameters of RTC controller according to the requested wakeup sources and power-down options.

It is also possible to enter sleep modes with no wakeup sources configured. In this case, the chip will be in sleep modes indefinitely until external reset is applied.

UART Output Handling

Before entering sleep mode, esp_deep_sleep_start() will flush the contents of UART FIFOs.

When entering Light-sleep mode using esp_light_sleep_start(), UART FIFOs will not be flushed. Instead, UART output will be suspended, and remaining characters in the FIFO will be sent out after wakeup from Light-sleep.

Checking Sleep Wakeup Cause

esp_sleep_get_wakeup_cause() function can be used to check which wakeup source has triggered wakeup from sleep mode.

For touchpad, it is possible to identify which touch pin has caused wakeup using esp_sleep_get_touchpad_wakeup_status() functions.

For ext1 wakeup sources, it is possible to identify which touch pin has caused wakeup using esp_sleep_get_ext1_wakeup_status() functions.

Application Example

• protocols/sntp demonstrates the implementation of basic functionality of Deep-sleep, where ESP module is periodically waken up to retrieve time from NTP server.

• wifi/power_save demonstrates the usage of Wi-Fi Modem-sleep mode and automatic Light-sleep feature to maintain Wi-Fi connections.

• bluetooth/nimble/power_save demonstrates the usage of Bluetooth Modem-sleep mode and automatic Light-sleep feature to maintain Bluetooth connections.

• system/deep_sleep demonstrates the usage of various Deep-sleep wakeup triggers and ULP coprocessor programming.

• system/light_sleep demonstrates the usage of Light-sleep wakeup triggered by various sources, such as the timer, GPIOs, the touch sensor, supported by ESP32.

API Reference

Header File

• components/esp_hw_support/include/esp_sleep.h

• This header file can be included with:

  #include "esp_sleep.h"
  

Functions

esp_err_t esp_sleep_disable_wakeup_source(esp_sleep_source_t source)

Disable wakeup source.

This function is used to deactivate wake up trigger for source defined as parameter of the function.

See docs/sleep-modes.rst for details.

Note

This function does not modify wake up configuration in RTC. It will be performed in esp_deep_sleep_start/esp_light_sleep_start function.

Parameters

source -- - number of source to disable of type esp_sleep_source_t

Returns

• ESP_OK on success

• ESP_ERR_INVALID_STATE if trigger was not active

esp_err_t esp_sleep_enable_ulp_wakeup(void)

Enable wakeup by ULP coprocessor.

Note

On ESP32, ULP wakeup source cannot be used when RTC_PERIPH power domain is forced, to be powered on (ESP_PD_OPTION_ON) or when ext0 wakeup source is used.

Returns

• ESP_OK on success

• ESP_ERR_NOT_SUPPORTED if additional current by touch (CONFIG_RTC_EXT_CRYST_ADDIT_CURRENT) is enabled.

• ESP_ERR_INVALID_STATE if ULP co-processor is not enabled or if wakeup triggers conflict

esp_err_t esp_sleep_enable_timer_wakeup(uint64_t time_in_us)

Enable wakeup by timer.

Parameters

time_in_us -- time before wakeup, in microseconds

Returns

• ESP_OK on success

• ESP_ERR_INVALID_ARG if value is out of range (TBD)

esp_err_t esp_sleep_enable_touchpad_wakeup(void)

Enable wakeup by touch sensor.

Note

On ESP32, touch wakeup source can not be used when RTC_PERIPH power domain is forced to be powered on (ESP_PD_OPTION_ON) or when ext0 wakeup source is used.

Note

The FSM mode of the touch button should be configured as the timer trigger mode.

Returns

• ESP_OK on success

• ESP_ERR_NOT_SUPPORTED if additional current by touch (CONFIG_RTC_EXT_CRYST_ADDIT_CURRENT) is enabled.

• ESP_ERR_INVALID_STATE if wakeup triggers conflict

touch_pad_t esp_sleep_get_touchpad_wakeup_status(void)

Get the touch pad which caused wakeup.

If wakeup was caused by another source, this function will return TOUCH_PAD_MAX;

Returns

touch pad which caused wakeup

bool esp_sleep_is_valid_wakeup_gpio(gpio_num_t gpio_num)

Returns true if a GPIO number is valid for use as wakeup source.

Note

For SoCs with RTC IO capability, this can be any valid RTC IO input pin.

Parameters

gpio_num -- Number of the GPIO to test for wakeup source capability

Returns

True if this GPIO number will be accepted as a sleep wakeup source.

esp_err_t esp_sleep_enable_ext0_wakeup(gpio_num_t gpio_num, int level)

Enable wakeup using a pin.

This function uses external wakeup feature of RTC_IO peripheral. It will work only if RTC peripherals are kept on during sleep.

This feature can monitor any pin which is an RTC IO. Once the pin transitions into the state given by level argument, the chip will be woken up.

Note

This function does not modify pin configuration. The pin is configured in esp_deep_sleep_start/esp_light_sleep_start, immediately before entering sleep mode.

Note

ESP32: ext0 wakeup source can not be used together with touch or ULP wakeup sources.

Parameters

• gpio_num -- GPIO number used as wakeup source. Only GPIOs with the RTC functionality can be used. For different SoCs, the related GPIOs are:

  • ESP32: 0, 2, 4, 12-15, 25-27, 32-39;

  • ESP32-S2: 0-21;

  • ESP32-S3: 0-21.

• level -- input level which will trigger wakeup (0=low, 1=high)

Returns

• ESP_OK on success

• ESP_ERR_INVALID_ARG if the selected GPIO is not an RTC GPIO, or the mode is invalid

• ESP_ERR_INVALID_STATE if wakeup triggers conflict

esp_err_t esp_sleep_enable_ext1_wakeup(uint64_t io_mask, esp_sleep_ext1_wakeup_mode_t level_mode)

Enable wakeup using multiple pins.

This function uses external wakeup feature of RTC controller. It will work even if RTC peripherals are shut down during sleep.

This feature can monitor any number of pins which are in RTC IOs. Once selected pins go into the state given by level_mode argument, the chip will be woken up.

Note

This function does not modify pin configuration. The pins are configured in esp_deep_sleep_start/esp_light_sleep_start, immediately before entering sleep mode.

Note

Internal pullups and pulldowns don't work when RTC peripherals are shut down. In this case, external resistors need to be added. Alternatively, RTC peripherals (and pullups/pulldowns) may be kept enabled using esp_sleep_pd_config function. If we turn off the RTC_PERIPH domain or certain chips lack the RTC_PERIPH domain, we will use the HOLD feature to maintain the pull-up and pull-down on the pins during sleep. HOLD feature will be acted on the pin internally before the system entering sleep, and this can further reduce power consumption.

Note

Call this func will reset the previous ext1 configuration.

Note

This function will be deprecated in release/v6.0. Please switch to use esp_sleep_enable_ext1_wakeup_io and esp_sleep_disable_ext1_wakeup_io

Parameters

• io_mask -- Bit mask of GPIO numbers which will cause wakeup. Only GPIOs which have RTC functionality can be used in this bit map. For different SoCs, the related GPIOs are:

  • ESP32: 0, 2, 4, 12-15, 25-27, 32-39

  • ESP32-S2: 0-21

  • ESP32-S3: 0-21

  • ESP32-C6: 0-7

  • ESP32-H2: 7-14

• level_mode -- Select logic function used to determine wakeup condition: When target chip is ESP32:

  • ESP_EXT1_WAKEUP_ALL_LOW: wake up when all selected GPIOs are low

  • ESP_EXT1_WAKEUP_ANY_HIGH: wake up when any of the selected GPIOs is high When target chip is ESP32-S2, ESP32-S3, ESP32-C6 or ESP32-H2:

  • ESP_EXT1_WAKEUP_ANY_LOW: wake up when any of the selected GPIOs is low

  • ESP_EXT1_WAKEUP_ANY_HIGH: wake up when any of the selected GPIOs is high

Returns

• ESP_OK on success

• ESP_ERR_INVALID_ARG if io_mask is zero,, or mode is invalid

esp_err_t esp_sleep_enable_ext1_wakeup_io(uint64_t io_mask, esp_sleep_ext1_wakeup_mode_t level_mode)

Enable ext1 wakeup pins with IO masks.

This will append selected IOs to the wakeup IOs, it will not reset previously enabled IOs. To reset specific previously enabled IOs, call esp_sleep_disable_ext1_wakeup_io with the io_mask. To reset all the enabled IOs, call esp_sleep_disable_ext1_wakeup_io(0).

This function uses external wakeup feature of RTC controller. It will work even if RTC peripherals are shut down during sleep.

This feature can monitor any number of pins which are in RTC IOs. Once selected pins go into the state given by level_mode argument, the chip will be woken up.

Note

This function does not modify pin configuration. The pins are configured in esp_deep_sleep_start/esp_light_sleep_start, immediately before entering sleep mode.

Note

Internal pullups and pulldowns don't work when RTC peripherals are shut down. In this case, external resistors need to be added. Alternatively, RTC peripherals (and pullups/pulldowns) may be kept enabled using esp_sleep_pd_config function. If we turn off the RTC_PERIPH domain or certain chips lack the RTC_PERIPH domain, we will use the HOLD feature to maintain the pull-up and pull-down on the pins during sleep. HOLD feature will be acted on the pin internally before the system entering sleep, and this can further reduce power consumption.

Parameters

• io_mask -- Bit mask of GPIO numbers which will cause wakeup. Only GPIOs which have RTC functionality can be used in this bit map. For different SoCs, the related GPIOs are:

  • ESP32: 0, 2, 4, 12-15, 25-27, 32-39

  • ESP32-S2: 0-21

  • ESP32-S3: 0-21

  • ESP32-C6: 0-7

  • ESP32-H2: 7-14

• level_mode -- Select logic function used to determine wakeup condition: When target chip is ESP32:

  • ESP_EXT1_WAKEUP_ALL_LOW: wake up when all selected GPIOs are low

  • ESP_EXT1_WAKEUP_ANY_HIGH: wake up when any of the selected GPIOs is high When target chip is ESP32-S2, ESP32-S3, ESP32-C6 or ESP32-H2:

  • ESP_EXT1_WAKEUP_ANY_LOW: wake up when any of the selected GPIOs is low

  • ESP_EXT1_WAKEUP_ANY_HIGH: wake up when any of the selected GPIOs is high

Returns

• ESP_OK on success

• ESP_ERR_INVALID_ARG if any of the selected GPIOs is not an RTC GPIO, or mode is invalid

• ESP_ERR_NOT_ALLOWED when wakeup level will become different between ext1 IOs if !SOC_PM_SUPPORT_EXT1_WAKEUP_MODE_PER_PIN

esp_err_t esp_sleep_disable_ext1_wakeup_io(uint64_t io_mask)

Disable ext1 wakeup pins with IO masks. This will remove selected IOs from the wakeup IOs.

Parameters

io_mask -- Bit mask of GPIO numbers which will cause wakeup. Only GPIOs which have RTC functionality can be used in this bit map. If value is zero, this func will remove all previous ext1 configuration. For different SoCs, the related GPIOs are:

• ESP32: 0, 2, 4, 12-15, 25-27, 32-39

• ESP32-S2: 0-21

• ESP32-S3: 0-21

• ESP32-C6: 0-7

• ESP32-H2: 7-14

Returns

• ESP_OK on success

• ESP_ERR_INVALID_ARG if any of the selected GPIOs is not an RTC GPIO.

esp_err_t esp_sleep_enable_gpio_wakeup(void)

Enable wakeup from light sleep using GPIOs.

Each GPIO supports wakeup function, which can be triggered on either low level or high level. Unlike EXT0 and EXT1 wakeup sources, this method can be used both for all IOs: RTC IOs and digital IOs. It can only be used to wakeup from light sleep though.

To enable wakeup, first call gpio_wakeup_enable, specifying gpio number and wakeup level, for each GPIO which is used for wakeup. Then call this function to enable wakeup feature.

Note

On ESP32, GPIO wakeup source can not be used together with touch or ULP wakeup sources.

Returns

• ESP_OK on success

• ESP_ERR_INVALID_STATE if wakeup triggers conflict

esp_err_t esp_sleep_enable_uart_wakeup(int uart_num)

Enable wakeup from light sleep using UART.

Use uart_set_wakeup_threshold function to configure UART wakeup threshold.

Wakeup from light sleep takes some time, so not every character sent to the UART can be received by the application.

Note

ESP32 does not support wakeup from UART2.

Parameters

uart_num -- UART port to wake up from

Returns

• ESP_OK on success

• ESP_ERR_INVALID_ARG if wakeup from given UART is not supported

esp_err_t esp_sleep_enable_bt_wakeup(void)

Enable wakeup by bluetooth.

Returns

• ESP_OK on success

• ESP_ERR_NOT_SUPPORTED if wakeup from bluetooth is not supported

esp_err_t esp_sleep_disable_bt_wakeup(void)

Disable wakeup by bluetooth.

Returns

• ESP_OK on success

• ESP_ERR_NOT_SUPPORTED if wakeup from bluetooth is not supported

esp_err_t esp_sleep_enable_wifi_wakeup(void)

Enable wakeup by WiFi MAC.

Returns

• ESP_OK on success

esp_err_t esp_sleep_disable_wifi_wakeup(void)

Disable wakeup by WiFi MAC.

Returns

• ESP_OK on success

esp_err_t esp_sleep_enable_wifi_beacon_wakeup(void)

Enable beacon wakeup by WiFi MAC, it will wake up the system into modem state.

Returns

• ESP_OK on success

esp_err_t esp_sleep_disable_wifi_beacon_wakeup(void)

Disable beacon wakeup by WiFi MAC.

Returns

• ESP_OK on success

uint64_t esp_sleep_get_ext1_wakeup_status(void)

Get the bit mask of GPIOs which caused wakeup (ext1)

If wakeup was caused by another source, this function will return 0.

Returns

bit mask, if GPIOn caused wakeup, BIT(n) will be set

esp_err_t esp_sleep_pd_config(esp_sleep_pd_domain_t domain, esp_sleep_pd_option_t option)

Set power down mode for an RTC power domain in sleep mode.

If not set set using this API, all power domains default to ESP_PD_OPTION_AUTO.

Parameters

• domain -- power domain to configure

• option -- power down option (ESP_PD_OPTION_OFF, ESP_PD_OPTION_ON, or ESP_PD_OPTION_AUTO)

Returns

• ESP_OK on success

• ESP_ERR_INVALID_ARG if either of the arguments is out of range

esp_err_t esp_deep_sleep_try_to_start(void)

Enter deep sleep with the configured wakeup options.

The reason for the rejection can be such as a short sleep time.

Note

In general, the function does not return, but if the sleep is rejected, then it returns from it.

Returns

• No return - If the sleep is not rejected.

• ESP_ERR_SLEEP_REJECT sleep request is rejected(wakeup source set before the sleep request)

void esp_deep_sleep_start(void)

Enter deep sleep with the configured wakeup options.

Note

The function does not do a return (no rejection). Even if wakeup source set before the sleep request it goes to deep sleep anyway.

esp_err_t esp_light_sleep_start(void)

Enter light sleep with the configured wakeup options.

Returns

• ESP_OK on success (returned after wakeup)

• ESP_ERR_SLEEP_REJECT sleep request is rejected(wakeup source set before the sleep request)

• ESP_ERR_SLEEP_TOO_SHORT_SLEEP_DURATION after deducting the sleep flow overhead, the final sleep duration is too short to cover the minimum sleep duration of the chip, when rtc timer wakeup source enabled

esp_err_t esp_deep_sleep_try(uint64_t time_in_us)

Enter deep-sleep mode.

The device will automatically wake up after the deep-sleep time Upon waking up, the device calls deep sleep wake stub, and then proceeds to load application.

Call to this function is equivalent to a call to esp_deep_sleep_enable_timer_wakeup followed by a call to esp_deep_sleep_start.

The reason for the rejection can be such as a short sleep time.

Note

In general, the function does not return, but if the sleep is rejected, then it returns from it.

Parameters

time_in_us -- deep-sleep time, unit: microsecond

Returns

• No return - If the sleep is not rejected.

• ESP_ERR_SLEEP_REJECT sleep request is rejected(wakeup source set before the sleep request)

void esp_deep_sleep(uint64_t time_in_us)

Enter deep-sleep mode.

The device will automatically wake up after the deep-sleep time Upon waking up, the device calls deep sleep wake stub, and then proceeds to load application.

Call to this function is equivalent to a call to esp_deep_sleep_enable_timer_wakeup followed by a call to esp_deep_sleep_start.

Note

The function does not do a return (no rejection).. Even if wakeup source set before the sleep request it goes to deep sleep anyway.

Parameters

time_in_us -- deep-sleep time, unit: microsecond

esp_err_t esp_deep_sleep_register_hook(esp_deep_sleep_cb_t new_dslp_cb)

Register a callback to be called from the deep sleep prepare.

Warning

deepsleep callbacks should without parameters, and MUST NOT, UNDER ANY CIRCUMSTANCES, CALL A FUNCTION THAT MIGHT BLOCK.

Parameters

new_dslp_cb -- Callback to be called

Returns

• ESP_OK: Callback registered to the deepsleep misc_modules_sleep_prepare

• ESP_ERR_NO_MEM: No more hook space for register the callback

void esp_deep_sleep_deregister_hook(esp_deep_sleep_cb_t old_dslp_cb)

Unregister an deepsleep callback.

Parameters

old_dslp_cb -- Callback to be unregistered

esp_sleep_wakeup_cause_t esp_sleep_get_wakeup_cause(void)

Get the wakeup source which caused wakeup from sleep.

Returns

cause of wake up from last sleep (deep sleep or light sleep)

void esp_wake_deep_sleep(void)

Default stub to run on wake from deep sleep.

Allows for executing code immediately on wake from sleep, before the software bootloader or ESP-IDF app has started up.

This function is weak-linked, so you can implement your own version to run code immediately when the chip wakes from sleep.

See docs/deep-sleep-stub.rst for details.

void esp_set_deep_sleep_wake_stub(esp_deep_sleep_wake_stub_fn_t new_stub)

Install a new stub at runtime to run on wake from deep sleep.

If implementing esp_wake_deep_sleep() then it is not necessary to call this function.

However, it is possible to call this function to substitute a different deep sleep stub. Any function used as a deep sleep stub must be marked RTC_IRAM_ATTR, and must obey the same rules given for esp_wake_deep_sleep().

void esp_set_deep_sleep_wake_stub_default_entry(void)

Set wake stub entry to default esp_wake_stub_entry

esp_deep_sleep_wake_stub_fn_t esp_get_deep_sleep_wake_stub(void)

Get current wake from deep sleep stub.

Returns

Return current wake from deep sleep stub, or NULL if no stub is installed.

void esp_default_wake_deep_sleep(void)

The default esp-idf-provided esp_wake_deep_sleep() stub.

See docs/deep-sleep-stub.rst for details.

void esp_deep_sleep_disable_rom_logging(void)

Disable logging from the ROM code after deep sleep.

Using LSB of RTC_STORE4.

void esp_sleep_config_gpio_isolate(void)

Configure to isolate all GPIO pins in sleep state.

void esp_sleep_enable_gpio_switch(bool enable)

Enable or disable GPIO pins status switching between slept status and waked status.

Parameters

enable -- decide whether to switch status or not

Macros

ESP_PD_DOMAIN_RTC8M

ESP_SLEEP_POWER_DOWN_CPU

Type Definitions

typedef void (*esp_deep_sleep_cb_t)(void)

typedef esp_sleep_source_t esp_sleep_wakeup_cause_t

typedef void (*esp_deep_sleep_wake_stub_fn_t)(void)

Function type for stub to run on wake from sleep.

Enumerations

enum esp_sleep_ext1_wakeup_mode_t

Logic function used for EXT1 wakeup mode.

Values:

enumerator ESP_EXT1_WAKEUP_ALL_LOW

Wake the chip when all selected GPIOs go low.

enumerator ESP_EXT1_WAKEUP_ANY_HIGH

Wake the chip when any of the selected GPIOs go high.

enum esp_sleep_pd_domain_t

Power domains which can be powered down in sleep mode.

Values:

enumerator ESP_PD_DOMAIN_RTC_PERIPH

RTC IO, sensors and ULP co-processor.

enumerator ESP_PD_DOMAIN_RTC_SLOW_MEM

RTC slow memory.

enumerator ESP_PD_DOMAIN_RTC_FAST_MEM

RTC fast memory.

enumerator ESP_PD_DOMAIN_XTAL

XTAL oscillator.

enumerator ESP_PD_DOMAIN_RC_FAST

Internal Fast oscillator.

enumerator ESP_PD_DOMAIN_VDDSDIO

VDD_SDIO.

enumerator ESP_PD_DOMAIN_MODEM

MODEM, includes WiFi, Bluetooth and IEEE802.15.4.

enumerator ESP_PD_DOMAIN_MAX

Number of domains.

enum esp_sleep_pd_option_t

Power down options.

Values:

enumerator ESP_PD_OPTION_OFF

Power down the power domain in sleep mode.

enumerator ESP_PD_OPTION_ON

Keep power domain enabled during sleep mode.

enumerator ESP_PD_OPTION_AUTO

Keep power domain enabled in sleep mode, if it is needed by one of the wakeup options. Otherwise power it down.

enum esp_sleep_source_t

Sleep wakeup cause.

Values:

enumerator ESP_SLEEP_WAKEUP_UNDEFINED

In case of deep sleep, reset was not caused by exit from deep sleep.

enumerator ESP_SLEEP_WAKEUP_ALL

Not a wakeup cause, used to disable all wakeup sources with esp_sleep_disable_wakeup_source.

enumerator ESP_SLEEP_WAKEUP_EXT0

Wakeup caused by external signal using RTC_IO.

enumerator ESP_SLEEP_WAKEUP_EXT1

Wakeup caused by external signal using RTC_CNTL.

enumerator ESP_SLEEP_WAKEUP_TIMER

Wakeup caused by timer.

enumerator ESP_SLEEP_WAKEUP_TOUCHPAD

Wakeup caused by touchpad.

enumerator ESP_SLEEP_WAKEUP_ULP

Wakeup caused by ULP program.

enumerator ESP_SLEEP_WAKEUP_GPIO

Wakeup caused by GPIO (light sleep only on ESP32, S2 and S3)

enumerator ESP_SLEEP_WAKEUP_UART

Wakeup caused by UART (light sleep only)

enumerator ESP_SLEEP_WAKEUP_WIFI

Wakeup caused by WIFI (light sleep only)

enumerator ESP_SLEEP_WAKEUP_COCPU

Wakeup caused by COCPU int.

enumerator ESP_SLEEP_WAKEUP_COCPU_TRAP_TRIG

Wakeup caused by COCPU crash.

enumerator ESP_SLEEP_WAKEUP_BT

Wakeup caused by BT (light sleep only)

enum esp_sleep_mode_t

Sleep mode.

Values:

enumerator ESP_SLEEP_MODE_LIGHT_SLEEP

light sleep mode

enumerator ESP_SLEEP_MODE_DEEP_SLEEP

deep sleep mode

enum [anonymous]

Values:

enumerator ESP_ERR_SLEEP_REJECT

enumerator ESP_ERR_SLEEP_TOO_SHORT_SLEEP_DURATION

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